Patent GB-1332448-A (GB)
Title: 7-heterocyclic substituted cephalosporins
IPC: C07D501/20
Filed: 1972-06-16
Abstract: 1332448 7-Heterocyclic substituted cephalosporins and heterocyclic substituted acetic acids SMITH KLINE & FRENCH LABORATORIES 16 June 1972 [21 June 1971] 28236/72 Headings C2A and C2C 7-Heterocyclic substituted cephalosporins of the Formula I wherein Het is an alkylated or unsubstituted 5- or 6-membered ring containing carbon and at least 2 hetero atoms selected from O, N and S; X is hydrogen, methoxy, acetoxy, methylthio, pyridinium, or Het<SP>1</SP>-S-; A is OH or NH 2 ; M is H, an alkali metal, or an organic ammonium ion; and Het<SP>1</SP> has the same significance as Het or is a 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2- pyrrolyl, 3-pyrrolyl, 2-pyridyl, 3-pyridyl or 4- pyridyl ring, which ring is optionally substituted by a C 1-6  alkyl group, with the proviso that when X is hydrogen, acetoxy or pyridinium, Het is not isothiazolyl, are prepared by acylating a compound of the formula the carboxyl group being protected as needed, with a compound of the formula or a functional derivative thereof, the OH or NH 2  group being protected as needed, and then removing any protective group to provide the product. Compounds of Formula I wherein X is Het<SP>1</SP>-S- or pyridinium are prepared by reacting a compound of Formula I wherein X is acetoxy, the NH 2  and, if desired, the OH group comprising A being protected as needed, with a compound of the formula Het<SP>1</SP>SH, or an alkali metal salt thereof, or with pyridine, respectively, and removing any protective group. The "Het" radical may be 2-, 4- or 5-thiazolyl; 2-, 4- or 5- oxazolyl; 3-, 4- or 5-isothiazolyl; 3-, 4- or 5- isoxazolyl; 1,2,3-thiadiazol-4-yl, 1,2,3- or 1,2,4- thiadiazol - 5 - yl, 1,2,5 - thiadiazol - 3 - yl, 1,3,4 - thiadiazol - 2 - yl; 1,2,4 - oxadiazol - 3- yl, 1,2,4 - oxadiazol - 5 - yl, 1,2,5 - oxadiazol- 3 - yl, 1,3,4 - oxadiazol - 2 - yl; imidazol - 2 - yl, imidazol-4-yl, tetrazolyl, 1,2,3-triazol-4-yl, 1,2, 4 - triazol - 3 - yl, pyrazol - 3 - yl, pyrazol - 4 - yl, pyrazinyl, pyrimidin-2-yl, pyrimidin-4-yl, pyrimidin - 5 - yl, pyridazin - 3 - yl, pyridazin - 4- yl, 1,2,3 - triazin - 4 - yl, 1,2,3 - triazin - 5 - yl, 1,2,4 - triazin - 3 - yl, 1,2,4 - triazin - 5 - yl, 1,2,4-triazin-6-yl and 1,3,5-triazin-2-yl. 2-Amino-2-(thiazol-4-yl) acetic acid is prepared by reacting ethyl thiazol-4-yl acetate and N- bromosuccinimide under irradiation to give the α-bromo-compound, which is reacted with sodium azide to give the α-azido compound, which is hydrogenated in the presence of hydrochloric acid to give the amine salt, which is treated with anion exchange resin to give the free amine. 2-Amino-2-(thiazol-5-yl)acetic acid is prepared by reacting ethyl-5-thiazole acetate and i-amylnitrite in ethanol with sodium to give ethyl α- oximidothiazol-5-yl acetate, which is treated with SnCl 2  and HCl to give the solid HCl salt, which is converted to the free amine acid by treatment with an ion exchange resin. 2-Amino-2-(3- methyl-1,2,5-oxadiazol-4-yl)acetic acid is prepared by converting (3-methyl-1,2,5-oxadiazol-4-yl)- acetic acid to its acid chloride by refluxing with thionyl chloride, the acid chloride is reacted with N-bromosuccinimide to give a mixture of the starting acid chloride and the α-bromo acid chloride which on treatment with water gives a mixture of unbrominated and α-brominated acetic acids, which upon treatment with concentrated ammonium hydroxide gives the desired amine acid. 2-Amino-2-(1,2,5-thiadiazol-3-yl)- acetic acid is prepared by refluxing 3-methyl- 1,2,5-thiadiazole and N-bromosuccinimide with U.V. irradiation to give 3-bromomethyl-1,2,5- thiadiazole, which upon treatment with sodium cyanide gives 1,2,5-thiadiazol-3-yl acetonitrile, which upon reflux in methanol and HCl gives methyl 1,2,5-thiadiazol-3-yl acetate, which upon reaction with N-bromosuccinimide gives methyl α-bromo-1,2,5-thiadiazol-3-yl acetate, which is hydrolysed to the corresponding α-bromo acid, which is treated with concentrated NH 4 OH to give the desired amine acid. 2-Amino-2-(1,5- dimethyl-pyrazol-3-yl)acetic acid is prepared by reacting 5 - methyl - 3 - formylpyrazole diethylacetal with NaH and methyl iodide to give 1,5- dimethyl-3-formyl pyrazole, which on treatment with NaCN and (NH 4 ) 2 CO 3  gives the hydantoin, which upon reflux with NaOH gives the desired amine acid. Antibacterial compositions comprise the above 7-heterocyclic substituted cephalosporins of Formula I and may be in forms suitable for oral or parenteral administration.